Fluid couplings are employed to interconnect components of pressurized fluid medium systems wherein the components may be selectively interconnected and disconnected. Manually operated couplings have long been employed to permit such interconnection, and various techniques have been used to reduce the forces required to assemble the coupling parts.
In many couplings for fluid systems at least one of the coupling parts includes a self-sealing valve retaining the pressurized fluid connected to that part, and the other coupling part includes means for displacing the self-sealing valve as the coupling parts are assembled. As the pressurized medium imposes a biasing force on the valve toward the closed condition the axial force produced by the pressurized medium must be overcome during the coupling assembly procedure. When using couplings in high pressure circuits, the axial forces required to connect the coupling parts due to pressurized force imposed on the valve may be very high rendering manual coupling difficult. For instance, breathing apparatus utilized by fire fighters wherein compressed air is supplied to pressure regulators operate at 4500 psi and the breathing apparatus must be connected to the compressed air tank while under such pressure.
It is an object of the invention to provide a connect-under-pressure coupling for use with pressurized fluid systems wherein at least one of the coupling parts includes a self-sealing valve, and wherein the valve construction is such that the valve operation is substantially unaffected by the pressure of the associated system.
Another object of the invention is to provide a connect-under-pressure coupling consisting of a pair of connectable parts each having axially displaceable self-sealing valves wherein each of the valves includes opposed faces exposed to the pressurized medium of substantially equal area to counter-balance axial forces imposed upon the valves by the medium.
An additional object of the invention is to provide a connect-under-pressure coupling having balanced axially displaceable self-sealing valves wherein the coupling configuration is concise and the components may be economically manufactured.
In the practice of the invention the connect-under-pressure coupling consists of two interconnectable parts, a male part and a female part, each having an axially displaceable self-sealing valve. As the parts are coupled the valves engage and simultaneously displace each other from their closed positions to open positions. Sealing between the parts occurs during coupling and uncoupling, and upon the parts being fully coupled, positive latch structure locks the assembled parts.
Each of the valves includes annular radially disposed faces exposed to the pressurized medium within the associated part. These faces may occur in sealing structure, and the faces associated with a common valve are in opposed axial relationship wherein the fluid forces imposed on the faces biases the associated valve in opposite axial directions. As the areas of the faces of a common valve are substantially equal, a balanced valve condition occurs such that, regardless of the extent of the pressure within the part, the effort required to displace the valve remains substantially constant. Compression springs are associated with the valves biasing the valves toward the closed position, and the springs are relatively weak so as not to significantly affect the axial coupling connection force, but the springs do insure that the valves will be biased to the closed position if the fluid system is unpressurized.
The coupling components are so related as to result in a concise configuration and yet the latch may be readily manually operated, even under adverse visibility conditions, and as the coupling permits the parts to be easily manually interconnected even with high pressure systems the coupling is readily usable with high pressure compressed air breathing systems.